The present invention relates generally to solenoid assemblies and, more particularly, to such assemblies utilized in valve actuation. Further, the present invention relates to rectilinear motion proportional solenoids.
This invention provides a novel improvement upon the invention disclosed in U.S. Pat. No. 4,463,332, which issued July 31, 1984 to one of the co-inventors of the present invention. Both inventions have been assigned to South Bend Controls, Inc. The complete disclosure and specification of that issued patent is specifically incorporated herein by reference.
In the past, valve housings and solenoid housings have been separately manufactured and assembled. Subsequently, these separate elements have been connected together to permit the solenoid to actuate the valve. For example, as shown in FIG. 1 of U.S. Pat. No. 4,463,332, valve housing 80 is connected to solenoid housing 12 via threads 14. However, forming the completed housing assembly from multiple component parts is time consuming and expensive. Further, additional sealing is required between the separate components, especially in wet coil environments. Also, multi-component assemblies are more susceptible to temperature instabilities, especially across the component junctures. In addition, since valve performance is typically critically dependant upon precise dimensioning and locating of the housing components, multi-component housings can have reduced performance ratings.
Further, an important concern with linear proportional solenoids is with the attachment of the springs within the solenoid. In the above-noted patent, for example, springs 69 and 70 were brazed into place at specially formed ridges 73. This brazing can cause certain metals to lose their temper. Furthermore, it was sometimes difficult to determine precisely how a specific material would react after such heating. As a result, post-brazing heat treatments and special metal alloys were used in the springs to retain the temper and maintain relatively consistent spring characteristics. Unfortunately, this can preclude utilization of more diverse specialty spring materials which would otherwise be desirable in particular valve environments.
Therefore, it is an object of the present invention to provide an improved housing and assembly for solenoid-actuated valve constructions.
Another object is the provision of a solenoid-valve assembly of reduced weight and manufacturing cost.
A further object is to provide a solenoid-valve assembly with improved temperature stability and performance characteristics.
Yet another object is the provision of a method of solenoid assembly wherein spring elements are secured without brazing.
Yet a further object is to provide a method of solenoid assembly wherein spring element composition and operating characteristics can be optimized for particular environments.
Yet still a further object is the provision of a solenoid actuated valve having improved versatility.
These and other objects of the present invention are attained by the provision of a valve-proportional solenoid arrangement in a unitary housing. The spring elements of the solenoid are mounted within this housing in the nature of a clamped cartridge. Fluid movement through the valve is adjustable by either movement of the valve seat or the solenoid polepiece within the housing. The solenoid elements are secured into the housing by a threaded cap at one end. The valve elements are secured into the housing by a threaded cap at another end. To assist in threaded securing of the armature to the retainer, in alternative embodiments portions of the circumference are flattened, although without altering the working area of the magnetic field with respect to the polepiece.
Other objects, advantages and novel features of the present invention will become readily apparent upon consideration of the following description of the preferred embodiments in conjunction with the drawings.